DEHISCENT FRUITS 



71 



pous pod or capsule — the word "syncarpous" meaning "of 

 united carpels." The three large, leaflike bodies at the 

 base of the cotton boll (none in the okra — unless very 

 immature pods are used — or the iris) are bracts, and to- 

 gether they form an involucre. Remove these and also 

 the remains of the flower cup, or calyx, that will be found 

 just within them, and notice the round, flatfish expansion 

 of the stem where the fruit is attached. Make a sketch of 

 the closed capsule, labeling this expansion receptacle, the 

 stem iV^^i peduncle, the longitudinal lines sutures, and the 



spaces between them carpels. 



Open the boll, or take one that 

 has already dehisced, remove 

 the lint with the seed from two 

 of the carpels, allowing them to 

 remain in the others, and sketch 

 the whole as it 

 appears on the in- 

 side. Notice the 

 protruding ridge 

 down the center of 

 each carpel which 

 divides the fruit, 

 when closed, into 

 separate chambers 

 or cells. Find out 

 to what part the seeds are attached and label it placenta. 

 The little threadlike stalks that attach the seed are 

 very small and hard to distinguish from the fleece, but 

 when they are broken away, their place can generally be 

 detected by small, toothlike projections on the placenta. 



In pods Hke those of okra, cotton, iris, etc., the placenta 

 is said to be parietal, from a Latin word meaning a wall, 

 because it projects from the wall of the seed vessel. From 

 which suture does it arise, the dorsal or the ventral.' 

 Which kind of sutures are those shown on the exterior of 

 the boll ? (Sees. 94, 98). Does it dehisce by the dorsal 

 or the ventral sutures .? Notice that when a capsule splits 



165 



163-165. — Capsule of okra : 163, entire, c, c, oar- 

 pels, r, receptacle, s, s, sutures ; 164, vertical section, 

 pi, placenta, 0, 0, ovu\ii%, /, f,faniculus, or seed stalk; 

 165, single carpel; 166, cross section, pi, placenta, 

 0, 0, ovules, s, s, sutures. 



